This invention relates generally to gas turbine engines and more particularly, to methods and apparatus for assembling fladed engines.
Variable cycle engines are conventionally known for powering high performance aircraft from subsonic to supersonic speeds while attempting to obtain countervailing objectives such as high specific thrust and low fuel consumption. In other words, ideal aircraft jet engines attempt to operate through various modes of thrust and speed requirements while minimizing fuel consumption.
Known variable cycle engines are generally operable over a range of operating conditions. In particular, conventional variable cycle combined turbojet or turbofan and ramjet engines generally attempt to provide for a range of operation from low subsonic Mach numbers to high supersonic Mach numbers of about Mach 6. However such turbofan-ramjet engines are relatively complex and generally include varying disadvantages. For example, at least one known turbofan-ramjet engine includes a ram burner which is wrapped around a core engine, thus creating an undesirably large diameter engine.
Other known variable cycle engines include variable coannular exhaust nozzles that are relatively complex and difficult to schedule the flow area thereof. Additionally, these known engines have a high level of base drag associated with the exhaust nozzles. Moreover, other known variable cycle engines include coannular, separate flow paths including a coannular inlet which creates an undesirably large inlet and which typically requires an inlet diverter valve for selectively channeling inlet air flow. These known engines may have high levels of spillage around the engine inlet. Other known engines may include one or more of such undesirable structures, thus resulting in an engine that is relatively complex, heavy, large, and inefficient.